A Snapshot-Based Mechanism for Celestial Orientation

Abstract

In order to protect their food from competitors, ball-rolling dung beetles detach a piece of dung from a pile, shape it into a ball, and roll it away along a straight path [1]. They appear to rely exclusively on celestial compass cues to maintain their bearing [2-8], but the mechanism that enables them to use these cues for orientation remains unknown. Here, we describe the orientation strategy that allows dung beetles to use celestial cues in a dynamic fashion. We tested the underlying orientation mechanism by presenting beetles with a combination of simulated celestial cues (sun, polarized light, and spectral cues). We show that these animals do not rely on an innate prediction of the natural geographical relationship between celestial cues, as other navigating insects seem to [9, 10]. Instead, they appear to form an internal representation of the prevailing celestial scene, a "celestial snapshot," even if that scene represents a physical impossibility for the real sky. We also find that the beetles are able to maintain their bearing with respect to the presented cues only if the cues are visible when the snapshot is taken. This happens during the "dance," a behavior in which the beetle climbs on top of its ball and rotates about its vertical axis [11]. This strategy for reading celestial signals is a simple but efficient mechanism for straight-line orientation.

Spatial orientation based on multiple visual cues in monarch butterflies

“…Some animals used both cues during flight, while other individuals relied predominantly on the simulated sun or the panoramic skyline as a reference. This indicates that the butterfly’s compass is capable of combining and weighting different visual cues, similar to what has been shown in ants and dung beetles (el Jundi et al, 2015b; el Jundi et al, 2016; Huber and Knaden, 2017). This is also similar to findings in the migrating Bogong moth which uses different modalities – the Earth’s magnetic field and dominant visual cues – for orientation (Dreyer et al, 2018a).…”

“…In nature, due to a different ratio of shorter (UV light) and longer (green light) wavelengths of light between the solar and anti-solar hemisphere, the direction of the sun can be determined based on a spectral contrast (Coemans et al, 1994; el Jundi et al, 2014). Whether monarch butterflies can use this spectral information, similar to what has been shown for bees (Brines and Gould, 1979; Edrich et al, 1979; Rossel and Wehner, 1984) and dung beetles (el Jundi et al, 2015a; el Jundi et al, 2016) remains to be shown in further experiments. In bees, a green light cue is interpreted as the sun while a UV light cue is treated as a patch of the sky somewhere in the anti-sun direction (Brines and Gould, 1979; Edrich et al, 1979; Rossel and Wehner, 1984).…”

Species-specific differences in the fine structure of learning walk elements inCataglyphisants

“…Learning flights of flying hymenoptera include repeated arcs, loops and turn-backs (honeybees : Becker, 1958;Capaldi and Dyer, 1999;Capaldi et al, 2000;Degen et al, 2015Degen et al, , 2016Lehrer, 1991Lehrer, , 1993Opfinger, 1931;Vollbehr, 1975;wasps: Peckham and Peckham, 1898;Stürzl et al, 2016;Tinbergen, 1932;Zeil, 1993a,b;Zeil et al, 1996;bumblebees: Collett et al, 2013;Hempel de Ibarra et al, 2009;Philippides et al, 2013;Riabinina et al, 2014;Robert et al, 2017;Wagner, 1907). Dung beetles perform rotations about their vertical axis before rolling a ball away from the dung pile (Baird et al, 2012), during which they take a snapshot of the celestial scenery (el Jundi et al, 2016). Desert spiders also perform learning walklike behavior: they leave their burrows in sinusoidal paths when departing to unfamiliar terrains (Nørgaard et al, 2012).…”

Kompass im Kopf

“…Interessanterweise rotieren auch Dungkäfer um 360° auf ihrer Dungkugel, um ihren Himmelskompass so einzurichten, dass sie sich anschließend geradlinig mit ihrer Dungkugel fortbewegen. Bevor sie mit ihrer Kugel losrollen, speichern sie den jeweils aktuellen Sonnenstand ab . Bei einer Pirouette hingegen bleiben die Ameisen stehen und drehen sich um ihre vertikale Körperachse.…”